Treatment of lignocellulosic substrates with ozone

Abstract

The invention relates to a process for the preparation of lignocellulosic substrates having a high digestibility. This process consists in bringing said lignocellulosic substrates, which have been ground beforehand and optionally moistened in the case of dry substrates, in a stirred reactor, into contact with ozone produced from a carrier gas, the ozone being present in the carrier gas in a concentration of between 80 and 200 g/m 3 NTP, with a residence time of between 8 and 40 min in said reactor. The invention further relates to the lignocellulosic substrates treated in this way.

1 . A method for preparing lignocellulosic substrates having high digestibility, comprising the steps of: 
 grinding said lignocellulosic substrates,    moistening the lignocellulosic substrates in the case of dry substrates, and    bringing the lignocellulosic substrates in a stirred reactor, into contact with ozone produced from a carrier gas, the ozone being present in the carrier gas in a concentration of between 80 and 200 g/m 3  NTP,    wherein the residence time in said reactor is between 8 and 40 min, and    wherein the moisture content of said substrates is between 1 and 6% based on the dry matter.    
     
     
         2 . A method according to  claim 1 , wherein the residence time is between 15 and 30 min.  
     
     
         3 . A method according to  claim 1 , wherein the concentration of ozone in the carrier gas is between 140 and 160 g/m 3  NTP.  
     
     
         4 . A method according to  claim 1 , wherein the moisture content of the lignocellulosic substrates is between 1 and 5%, based on the dry matter.  
     
     
         5 . A method according to  claim 1 , wherein the size of the ground lignocellulosic substrates is between 5 mm to 20 mm.  
     
     
         6 . A method according to  claim 1 , wherein the relative pressure of the ozonized carrier gas when it is brought into contact with said substrates is between 0.6 and 1.5 bar.  
     
     
         7 . A method according to  claim 1 , wherein the lignocellulosic substrates are selected from the group consisting of dry substrates and moist substrates.  
     
     
         8 . A lignocellulosic substrate obtainable by the method according to  claim 1 .  
     
     
         9 . A method according to  claim 1 , wherein the size of the ground lignocellulosic substrates is between 10 mm to 20 mm.  
     
     
         10 . A method according to  claim 1 , wherein the relative pressure of the ozonized carrier, gas when it is brought into contact with said substrates is between 0.6 and 1.2 bar.  
     
     
         11 . A method according to  claim 7 , wherein the dry substrates are selected from the group consisting of rye, wheat and alfalfa straws, sugar beet cossettes and cereal grains.  
     
     
         12 . A method according to  claim 7 , wherein the moist substrates are selected from the group consisting of sugar cane bagasse, sorghums, ray grasses and hays.